Saturday night Manny Pacquiao will be in danger simply because it seems there is no danger lurking across the ring from him at the Mandalay Bay Events Center.

The widely held supposition is that with the retirement of Floyd Mayweather, Jr., Pacquiao is the best fighter, pound-for-pound, in the world. Because of that it is nearly universally believed that WBC lightweight champion David Diaz is merely in Las Vegas as a foil, a highly paid sparring partner there to hand over his title with a fight but not much of one.

Diaz is supposed to be a sacrificial lamb brought in because Pacquiao needs both an opponent and a fourth world title and since both fighters have the same promoter why not let Diaz be the painful beneficiary of Pacquiao’s needs?

The danger then is not so much Diaz himself, although he is a tough hombre from Chicago who comes to fight all night long, but rather that it is difficult not to believe such widely held opinions when you hear them over and over and read them in newspapers written in many languages.

Manny Pacquiao and his trainer, Freddie Roach, can publicly give Diaz all the respect they want but the fact of the matter is they believe the same thing the public believes. They believe this is to be a coronation not a collision on HBO, even though they understand it is just that kind of thinking that can make it far more of the latter than anyone might have reason to expect if Pacquiao becomes careless.

Even though Pacquiao is moving up to 135 pounds for the first time while Diaz has been at that weight throughout his professional career, the argument is that this will only make one of the most popular fighters in the world stronger. Already considered one of the hardest punchers in boxing at between 122 to 130 pounds, Pacquiao expects he will be even more lethal at 135 and he might be. Then again, he might not because he wouldn’t be the first fighter to find he has moved up in weight but left his power behind.

Add to that the fact he’ll be getting hit by a naturally bigger man, assuming he gets hit at all, and one can see the potential problems if one looks hard enough. But is Manny Pacquiao looking at all?

“Sometimes it’s hard to get motivated to fight a guy like him because he’s not a name guy like (Erik) Morales or (Marco Antonio) Barrera,’’ Pacquiao admitted earlier this week. “But I have to fight him and I had to get in shape to do it. And I’m in great shape.’’

Physically he surely is, although Roach has publicly spoken of his concern that Pacquiao may re-gain too much weight between the weigh-in and the fight and thus become sluggish if the bout drags into the latter rounds.

Roach claims that is what happened in Pacquiao’s last fight with Juan Manuel Marquez, when he ballooned up by nearly 20 pounds from the weigh-in to the first bell. It is his hope that because Pacquiao didn’t have to starve himself to make weight this time that he will not feel driven to gorge on everything he can get his hands on in the final 24 hours before the fight and thus avoid that potential pitfall.

Yet even if that is true and he feels more content at 135 danger lurks there as well because while Pacquiao may indeed be stronger at 135 than he was at 130 no one can guarantee that that will make him a better fighter, even though that too seems to be his supposition.

“I’m not worried about punching power,’’ Pacquiao said. “In training camp I was sparring with 145 pounders. I don’t think he’s stronger. I believe that I’m stronger than him.

“You know, moving up in weight it’s not easy. I have to maintain that speed and power. The power is no concern. I feel stronger at 135. What we’ve been working on is to maintain my speed because with moving up there is a chance to get slower.

“It’s not easy to move up but for me at 135, I’m very comfortable at that weight. Some people are saying that it’s hard for me to fight at 135 pounds but fighting bigger guys is definitely not a problem for me. I believe I’m stronger at 135 pounds.’’

Belief in yourself is a good thing. Belief at the expense of caution about the downside possibilities however can be foolhardy and so Pacquiao is walking a thin line between confidence and danger, danger he might not realize exists until it becomes painfully apparent.

If that happens, he will recognize the depth of his problem too late. That doesn’t mean he might not still find a way to win but it would become a far more difficult task than anyone but perhaps Diaz is expecting.

“I have my own opinion of myself and that’s all that matters,’’ Diaz (34-1) said confidently. “I pay no mind to what other people say. They are going to say what they want.  This is my chance to knock down the wall and Manny is the wall.’’

Those do not sound like the words of someone who believes the hype. It is not what you say if you came to Las Vegas only to serve as cannon fodder for a more popular and better known opponent. In the end, of course, words are empty because the fighters decide. On that both Pacquiao and Diaz agree.

The world assumes the fighter who will do that is Manny Pacquiao and they may very well be right. He has more speed than Diaz, who admits he is a bit of a plodder. He has more power and he certainly has beaten better competition. Yet none of that will matter Saturday night. All that will matter is what happens in that moment when the two of them collide, which is the beauty and the fascination of boxing.

Pacquiao is a heavy favorite to win for good reasons. Probably not even Diaz would try to argue that he is a more skilled fighter than Pacquiao yet he knows skills will come into play only if Pacquiao first remembers that across the ring from him stands a fighter, not an actor. A fighter with pride and heart and as much desire to defend the lightweight title he holds as Pacquiao has to take it from him.

If Manny Pacquiao is able to convince himself of that in the final hours leading up to Saturday night’s confrontation with David Diaz he seems likely to do fine. But if he has come to believe danger has taken the night off in Las Vegas another story could yet be written. One like an Agatha Christie mystery – with an unexpected twist at the end.